X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/146ad4c8d055b498632ee6f2a3079878607a7ffb..e89a22bfab22e4d2ee73be49dcb66b51f8d0e892:/src/LR0.c

diff --git a/src/LR0.c b/src/LR0.c
index 8d424eab..3fa5ba5b 100644
--- a/src/LR0.c
+++ b/src/LR0.c
@@ -30,7 +30,7 @@
 #include "complain.h"
 #include "closure.h"
 #include "LR0.h"
-
+#include "reduce.h"
 
 int nstates;
 int final_state;
@@ -50,7 +50,7 @@ static short *redset = NULL;
 static short *shiftset = NULL;
 
 static short **kernel_base = NULL;
-static size_t *kernel_size = NULL;
+static int *kernel_size = NULL;
 static short *kernel_items = NULL;
 
 /* hash table for states, to recognize equivalent ones.  */
@@ -63,11 +63,13 @@ static void
 allocate_itemsets (void)
 {
   int i;
-  int count;
-  short *symbol_count = NULL;
 
-  count = 0;
-  symbol_count = XCALLOC (short, nsyms);
+  /* Count the number of occurrences of all the symbols in RITEMS.
+     Note that useless productions (hence useless nonterminals) are
+     browsed too, hence we need to allocate room for _all_ the
+     symbols.  */
+  int count = 0;
+  short *symbol_count = XCALLOC (short, nsyms + nuseless_nonterminals);
 
   for (i = 0; ritem[i]; ++i)
     if (ritem[i] > 0)
@@ -93,8 +95,8 @@ allocate_itemsets (void)
       count += symbol_count[i];
     }
 
-  shift_symbol = symbol_count;
-  kernel_size = XCALLOC (size_t, nsyms);
+  free (symbol_count);
+  kernel_size = XCALLOC (int, nsyms);
 }
 
 
@@ -112,13 +114,13 @@ allocate_storage (void)
 static void
 free_storage (void)
 {
-  XFREE (shift_symbol);
-  XFREE (redset);
-  XFREE (shiftset);
-  XFREE (kernel_base);
-  XFREE (kernel_size);
+  free (shift_symbol);
+  free (redset);
+  free (shiftset);
+  free (kernel_base);
+  free (kernel_size);
   XFREE (kernel_items);
-  XFREE (state_table);
+  free (state_table);
 }
 
 
@@ -139,7 +141,6 @@ static void
 new_itemsets (void)
 {
   int i;
-  int shiftcount;
 
   if (trace_flag)
     fprintf (stderr, "Entering new_itemsets, state = %d\n",
@@ -148,25 +149,24 @@ new_itemsets (void)
   for (i = 0; i < nsyms; i++)
     kernel_size[i] = 0;
 
-  shiftcount = 0;
+  shift_symbol = XCALLOC (short, nsyms);
+  nshifts = 0;
 
-  for (i = 0; i < itemsetsize; ++i)
+  for (i = 0; i < nitemset; ++i)
     {
       int symbol = ritem[itemset[i]];
       if (symbol > 0)
 	{
 	  if (!kernel_size[symbol])
 	    {
-	      shift_symbol[shiftcount] = symbol;
-	      shiftcount++;
+	      shift_symbol[nshifts] = symbol;
+	      nshifts++;
 	    }
 
 	  kernel_base[symbol][kernel_size[symbol]] = itemset[i] + 1;
 	  kernel_size[symbol]++;
 	}
     }
-
-  nshifts = shiftcount;
 }
 
 
@@ -213,7 +213,6 @@ static int
 get_state (int symbol)
 {
   int key;
-  short *isp2;
   int i;
   core *sp;
 
@@ -236,7 +235,6 @@ get_state (int symbol)
 	{
 	  if (sp->nitems == kernel_size[symbol])
 	    {
-	      int i;
 	      found = 1;
 	      for (i = 0; i < kernel_size[symbol]; ++i)
 		if (kernel_base[symbol][i] != sp->items[i])
@@ -313,13 +311,16 @@ new_states (void)
 }
 
 
+/*------------------------------------------------------------.
+| Save the NSHIFTS of SHIFTSET into the current linked list.  |
+`------------------------------------------------------------*/
+
 static void
 save_shifts (void)
 {
-  shifts *p = SHIFTS_ALLOC (nshifts);
+  shifts *p = shifts_new (nshifts);
 
   p->number = this_state->number;
-  p->nshifts = nshifts;
 
   shortcpy (p->shifts, shiftset, nshifts);
 
@@ -350,9 +351,8 @@ insert_start_shift (void)
   last_state = statep;
 
   /* Make a shift from this state to (what will be) the final state.  */
-  sp = SHIFTS_ALLOC (1);
+  sp = shifts_new (1);
   sp->number = nstates++;
-  sp->nshifts = 1;
   sp->shifts[0] = nstates;
 
   last_shift->next = sp;
@@ -371,118 +371,110 @@ insert_start_shift (void)
 static void
 augment_automaton (void)
 {
-  int i;
-  int k;
   core *statep;
   shifts *sp;
-  shifts *sp2;
   shifts *sp1 = NULL;
 
   sp = first_shift;
 
-  if (sp)
+  if (!sp->nshifts)
     {
-      if (sp->number == 0)
-	{
-	  k = sp->nshifts;
-	  statep = first_state->next;
-
-	  /* The states reached by shifts from first_state are numbered 1...K.
-	     Look for one reached by start_symbol.  */
-	  while (statep->accessing_symbol < start_symbol
-		 && statep->number < k)
-	    statep = statep->next;
+      /* There are no shifts for any state.  Make one shift, from the
+	 initial state to the next-to-final state.  */
 
-	  if (statep->accessing_symbol == start_symbol)
-	    {
-	      /* We already have a next-to-final state.
-	         Make sure it has a shift to what will be the final state.  */
-	      k = statep->number;
+      sp = shifts_new (1);
+      sp->shifts[0] = nstates;
 
-	      while (sp && sp->number < k)
-		{
-		  sp1 = sp;
-		  sp = sp->next;
-		}
+      /* Initialize the chain of shifts with sp.  */
+      first_shift = sp;
+      last_shift = sp;
 
-	      if (sp && sp->number == k)
-		{
-		  sp2 = SHIFTS_ALLOC (sp->nshifts + 1);
-		  sp2->number = k;
-		  sp2->nshifts = sp->nshifts + 1;
-		  sp2->shifts[0] = nstates;
-		  for (i = sp->nshifts; i > 0; i--)
-		    sp2->shifts[i] = sp->shifts[i - 1];
-
-		  /* Patch sp2 into the chain of shifts in place of sp,
-		     following sp1.  */
-		  sp2->next = sp->next;
-		  sp1->next = sp2;
-		  if (sp == last_shift)
-		    last_shift = sp2;
-		  XFREE (sp);
-		}
-	      else
-		{
-		  sp2 = SHIFTS_ALLOC (1);
-		  sp2->number = k;
-		  sp2->nshifts = 1;
-		  sp2->shifts[0] = nstates;
-
-		  /* Patch sp2 into the chain of shifts between sp1 and sp.  */
-		  sp2->next = sp;
-		  sp1->next = sp2;
-		  if (sp == 0)
-		    last_shift = sp2;
-		}
-	    }
-	  else
-	    {
-	      /* There is no next-to-final state as yet.  */
-	      /* Add one more shift in first_shift,
-	         going to the next-to-final state (yet to be made).  */
-	      sp = first_shift;
+      /* Create the next-to-final state, with shift to
+         what will be the final state.  */
+      insert_start_shift ();
+    }
+  else if (sp->number == 0)
+    {
+      statep = first_state->next;
 
-	      sp2 = SHIFTS_ALLOC (sp->nshifts + 1);
-	      sp2->nshifts = sp->nshifts + 1;
+      /* The states reached by shifts from FIRST_STATE are numbered
+	 1..(SP->NSHIFTS).  Look for one reached by START_SYMBOL.  */
+      while (statep->accessing_symbol < start_symbol
+	     && statep->number < sp->nshifts)
+	statep = statep->next;
 
-	      /* Stick this shift into the vector at the proper place.  */
-	      statep = first_state->next;
-	      for (k = 0, i = 0; i < sp->nshifts; k++, i++)
-		{
-		  if (statep->accessing_symbol > start_symbol && i == k)
-		    sp2->shifts[k++] = nstates;
-		  sp2->shifts[k] = sp->shifts[i];
-		  statep = statep->next;
-		}
-	      if (i == k)
-		sp2->shifts[k++] = nstates;
+      if (statep->accessing_symbol == start_symbol)
+	{
+	  /* We already have a next-to-final state.
+	     Make sure it has a shift to what will be the final state.  */
+	  while (sp && sp->number < statep->number)
+	    {
+	      sp1 = sp;
+	      sp = sp->next;
+	    }
 
-	      /* Patch sp2 into the chain of shifts
-	         in place of sp, at the beginning.  */
+	  if (sp && sp->number == statep->number)
+	    {
+	      int i;
+	      shifts *sp2 = shifts_new (sp->nshifts + 1);
+	      sp2->number = statep->number;
+	      sp2->shifts[0] = nstates;
+	      for (i = sp->nshifts; i > 0; i--)
+		sp2->shifts[i] = sp->shifts[i - 1];
+
+	      /* Patch sp2 into the chain of shifts in place of sp,
+		 following sp1.  */
 	      sp2->next = sp->next;
-	      first_shift = sp2;
-	      if (last_shift == sp)
+	      sp1->next = sp2;
+	      if (sp == last_shift)
 		last_shift = sp2;
-
 	      XFREE (sp);
-
-	      /* Create the next-to-final state, with shift to
-	         what will be the final state.  */
-	      insert_start_shift ();
+	    }
+	  else
+	    {
+	      shifts *sp2 = shifts_new (1);
+	      sp2->number = statep->number;
+	      sp2->shifts[0] = nstates;
+
+	      /* Patch sp2 into the chain of shifts between sp1 and sp.  */
+	      sp2->next = sp;
+	      sp1->next = sp2;
+	      if (sp == 0)
+		last_shift = sp2;
 	    }
 	}
       else
 	{
-	  /* The initial state didn't even have any shifts.
-	     Give it one shift, to the next-to-final state.  */
-	  sp = SHIFTS_ALLOC (1);
-	  sp->nshifts = 1;
-	  sp->shifts[0] = nstates;
+	  int i, k;
+	  shifts *sp2;
+
+	  /* There is no next-to-final state as yet.  */
+	  /* Add one more shift in first_shift,
+	     going to the next-to-final state (yet to be made).  */
+	  sp = first_shift;
+
+	  sp2 = shifts_new (sp->nshifts + 1);
+
+	  /* Stick this shift into the vector at the proper place.  */
+	  statep = first_state->next;
+	  for (k = 0, i = 0; i < sp->nshifts; k++, i++)
+	    {
+	      if (statep->accessing_symbol > start_symbol && i == k)
+		sp2->shifts[k++] = nstates;
+	      sp2->shifts[k] = sp->shifts[i];
+	      statep = statep->next;
+	    }
+	  if (i == k)
+	    sp2->shifts[k++] = nstates;
 
-	  /* Patch sp into the chain of shifts at the beginning.  */
-	  sp->next = first_shift;
-	  first_shift = sp;
+	  /* Patch sp2 into the chain of shifts
+	     in place of sp, at the beginning.  */
+	  sp2->next = sp->next;
+	  first_shift = sp2;
+	  if (last_shift == sp)
+	    last_shift = sp2;
+
+	  XFREE (sp);
 
 	  /* Create the next-to-final state, with shift to
 	     what will be the final state.  */
@@ -491,19 +483,17 @@ augment_automaton (void)
     }
   else
     {
-      /* There are no shifts for any state.
-         Make one shift, from the initial state to the next-to-final state.  */
-
-      sp = SHIFTS_ALLOC (1);
-      sp->nshifts = 1;
+      /* The initial state didn't even have any shifts.
+	 Give it one shift, to the next-to-final state.  */
+      sp = shifts_new (1);
       sp->shifts[0] = nstates;
 
-      /* Initialize the chain of shifts with sp.  */
+      /* Patch sp into the chain of shifts at the beginning.  */
+      sp->next = first_shift;
       first_shift = sp;
-      last_shift = sp;
 
       /* Create the next-to-final state, with shift to
-         what will be the final state.  */
+	 what will be the final state.  */
       insert_start_shift ();
     }
 
@@ -516,9 +506,8 @@ augment_automaton (void)
   last_state = statep;
 
   /* Make the shift from the final state to the termination state.  */
-  sp = SHIFTS_ALLOC (1);
+  sp = shifts_new (1);
   sp->number = nstates++;
-  sp->nshifts = 1;
   sp->shifts[0] = nstates;
   last_shift->next = sp;
   last_shift = sp;
@@ -550,7 +539,7 @@ save_reductions (void)
   /* Find and count the active items that represent ends of rules. */
 
   count = 0;
-  for (i = 0; i < itemsetsize; ++i)
+  for (i = 0; i < nitemset; ++i)
     {
       int item = ritem[itemset[i]];
       if (item < 0)
@@ -591,6 +580,9 @@ generate_states (void)
 
   while (this_state)
     {
+      if (trace_flag)
+	fprintf (stderr, "Processing state %d (reached by %s)\n",
+		 this_state->number, tags[this_state->accessing_symbol]);
       /* Set up ruleset and itemset for the transitions out of this
          state.  ruleset gets a 1 bit for each rule that could reduce
          now.  itemset gets a vector of all the items that could be
@@ -605,8 +597,7 @@ generate_states (void)
 
       /* create the shifts structures for the shifts to those states,
          now that the state numbers transitioning to are known */
-      if (nshifts > 0)
-	save_shifts ();
+      save_shifts ();
 
       /* states are queued when they are created; process them all */
       this_state = this_state->next;